Another casualty of edc78205d5. This
particular button was actually *relying* on receiving positional events
from its entire bounding box rather than `Content`, in order for the
button to be htitable more easily, which broke as other buttons were
fixed to behave more in line with expectations.
Upon closer inspection this is another case of a weird carried-over
construction. The button doesn't really need to inherit `OsuButton` or
do any of the arcane stuff that it was doing, so it's now a plain
`OsuClickableContainer` with less `Content` hackery.
Having both was a bit too much. Still not happy with this but it's a bit
less sensory overload.
I think while it's cool being able to show nested screens like this, it
needs more thought to actually be a good experience.